One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,12)(13,17)(14,15)(16,19)(18,20)(21,24)(22,23)(25,26)(27,34)(28,31)(29,33)(30,32)(35,40)(36,37)(38,39) involution — undirected(2,3)(6,7)(10,15)(12,16)(17,23)(20,21)(25,27,31,30)(26,32,28,34)(29,35,37,38)(33,39,36,40)(1,2,5,3)(4,6,8,7)(26,28)(32,34)(33,36)(39,40)(9,11)(10,16)(12,15)(13,18)(14,19)(17,21)(20,23)(22,24)(25,28,31,26)(27,34,30,32)(29,36,37,33)(35,40,38,39)(1,3,5,2)(4,6,8,7)(9,12,14,16)(10,11,15,19)(13,21,22,20)(17,24,23,18)(25,29)(26,33)(27,35)(28,36)(30,38)(31,37)(32,39)(34,40)(1,4)(2,6)(3,7)(5,8)(9,13,14,22)(10,17,15,23)(11,18,19,24)(12,20,16,21)(25,30,31,27)(26,34,28,32)(29,35,37,38)(33,39,36,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.